The present invention relates generally to operations performed and equipment utilized in conjunction with subterranean wells and, in an embodiment described herein, more particularly provides a multilateral well completion.
Those skilled in the art know that it is very difficult to form a sealed junction between intersecting wellbores in a well. The environment is hostile and very remote from the earth""s surface. For this reason, systems developed to form wellbore junctions categorized in the industry as TAML level 5 and above tend to be very sophisticated and, accordingly, very expensive.
What is needed is a multilateral well completion system which may be used to form a TAML level 5 or above wellbore junction, but which is relatively inexpensive to construct and straightforward in its installation.
In carrying out the principles of the present invention, in accordance with an embodiment thereof, a multilateral well completion system is provided which satisfies the above described need in the art. Also provided are multilateral well completion apparatus and methods.
In one aspect of the invention, a multilateral well completion system is provided. A parent wellbore is lined with a casing string. A branch wellbore extends outwardly from a window in the casing string. A completion apparatus is positioned within the parent wellbore, the apparatus including inner and outer tubular structures, the outer tubular structure extending in the parent wellbore on opposite sides of the window, the outer tubular structure having an opening in a sidewall thereof aligned with the window, the inner tubular structure extending longitudinally within the outer tubular structure to the opening, and a longitudinal flow passage formed through the inner tubular structure extending through the opening.
In another aspect of the invention, a multilateral well completion apparatus is provided. The apparatus includes inner and outer tubular structures. A first portion of the inner tubular structure extends longitudinally within the outer tubular structure, thereby forming an annulus therebetween. A second portion of the inner tubular structure deviates laterally relative to the outer tubular structure, so that a longitudinal flow passage of the inner tubular structure extends outwardly through an opening formed through a sidewall of the outer tubular structure.
In yet another aspect of the invention, a method of completing a multilateral well is provided. The method includes the steps of: installing a completion apparatus in a parent wellbore having a window formed in casing lining the parent wellbore; rotationally aligning the completion apparatus relative to the window, thereby aligning an opening in a sidewall of an outer tubular structure of the apparatus with a branch wellbore extending outwardly from the window; and inserting a tubular string through an inner tubular structure of the completion apparatus, the inner tubular structure thereby directing the tubular string to deviate laterally out the opening, through the window, and into the branch wellbore.
These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of a representative embodiment of the invention hereinbelow and the accompanying drawings.